Leading article: The irresistible case for a public enquiry

Hindsight is always an over-rated faculty, and it is quite possible that nothing at all could have prevented four disaffected British Muslims from killing themselves and 52 Tube and bus passengers in London on 7 July last year. But the general hand-wringing that emerges from the two reports that have now seen the light of day - the one by the parliamentary Intelligence and Security Committee, the other an official government "narrative" - amounts to a far from satisfactory verdict on the gravest peace-time attack on mainland Britain.

We say this not because the ISC decided that there were no "culpable failures" in the intelligence operation. MPs have studied the evidence and concluded that, although there were failures, there was no real blame to be assigned. They are entitled to their view: the search for a scapegoat whenever something bad happens is never edifying. It is sometimes better to acknowledge that disasters and oversights happen. We say it because the intelligence services seem to have been given the benefit of rather too many doubts and because so many legitimate questions remain without an answer.

The bombers were in contact with someone in Pakistan just before they struck, but no further details were apparently established. Two of them may have attended training camps in Pakistan, but the conclusion is that the plot was probably hatched in Britain and "inspired" - rather than ordered - by al-Qa'ida.

The ISC observes that the chances of preventing the attacks might have been greater had different investigative decisions been made by MI5. But the committee's view that the response of the authorities might have been different had the security services appreciated how swiftly even British citizens could become suicide bombers seems unduly timid . It is the job of the intelligence services to be aware of such eventualities; that they were not reflects poorly on their judgement.

It is disappointing therefore to find that the ISC's chief recommendation is for more resources - ie money - to be allocated to the security services. Money alone is no substitute for insight and sound decision-making. The government report is equally disappointing, in a different way. By restricting themselves to an account of what happened, rather than considering the hows and whys, ministers are simply ducking responsibility. The impact of the Iraq war on the climate of Muslim opinion seems also to have been neglected.

If anything cries out for a full public inquiry, it is the London bombings. Yet the Government argues that such an inquiry would be a waste of time and money. As with Iraq, ministers prefer separate, narrowly-drawn investigations to a public inquiry that could dictate its own terms and slip out of control. We cannot but ask why they are so afraid.